Counterweight method for national standard 1 # gold ingot

Abstract

The invention belongs to the field of precious metal metallurgy, and particularly relates to a counterweight method of a national standard 1 # gold ingot, which comprises the following steps of: configuring two graphite crucibles in an intermediate frequency furnace, alternately using, melting a gold raw material, adding a slag former for slagging, casting, pressing the gold ingot into a slice, cutting into a gold block, and counterweight. According to the method, the adaptability of the gold raw materials is good, the gold raw materials with single impurities exceeding the standard and the gold color lower than the national standard 1 # gold standard can be treated, the gold raw materials do not need to enter a purification system for purification again, the production period is greatly shortened, the production efficiency is improved, the cost is saved, the method is suitable for large-scale production, the produced gold ingots are stable in color, and the method has good popularization value.

Description

Technical Field

[0001] The invention belongs to the field of precious metal pyrometallurgy, and in particular relates to a weight balancing method for a national standard 1# gold ingot. Background Art

[0002] According to the Shanghai Gold Exchange's warehousing requirements, the total purity of 1# gold ingots should be greater than 99.99%, and the individual impurities must meet the national gold ingot standards. In order to avoid gold ingot testing errors at various refineries, the actual requirement is that the gold ingot purity should be greater than 99.992%. At present, the raw material supply of the national standard 1# gold ingot adopts the granulation method for weighting.

[0003] The granulation method uses a closed furnace to melt the gold raw material, then reduces the power to the gold liquid insulation state, lifts the graphite plug in the middle of the furnace, and the gold liquid flows out from the graphite discharge port. The graphite discharge port is evenly distributed with 10 holes with a diameter of 1mm. A stainless steel water tank is placed below the discharge port, and a circulating water pump is configured. The circulating water pump stirs the cooling water to make the gold liquid granular in the water. After granulation, the gold particles are taken out for drying and weighting. Due to the use of a closed furnace, this method must control the power for heat dissipation and safety considerations. The production cycle is long, and the amount of feeding per furnace is small, resulting in low overall production efficiency. The discharge port aperture is small, the discharge speed is slow, and increasing the aperture will cause the gold particles to agglomerate, which is not convenient for subsequent weighting, and it takes 30 minutes to dry the gold particles. The entire granulation process requires nitrogen protection. The nitrogen in the entire cavity needs to be discharged during the feeding process, otherwise it will cause combustion and explosion, which poses certain safety hazards. The gold raw material melting process uses high-frequency melting, and the gold liquid cannot effectively roll under the action of the magnetic field, resulting in inconsistent gold particle composition, affecting the quality of the gold ingot. This method cannot oxidize and slag the gold liquid, so the adaptability of gold raw materials is poor.

[0004] In view of the many defects of the granulation method, the industry urgently needs to find a weighting method for 1# gold ingots with strong raw material adaptability, short production cycle, high production efficiency, safety and environmental protection, and stable gold ingot color. Summary of the invention

[0005] The purpose of the present invention is to provide a weighting method for national standard 1# gold ingots in view of the shortcomings of the above-mentioned existing granulation technology, which can efficiently and stably weight the national standard 1# gold ingots for raw materials with excessive single impurities and gold purity lower than the national standard 1#.

[0006] The specific technical scheme is: a weighting method for a national standard 1# gold ingot, using a medium frequency furnace equipped with two graphite crucibles and using them alternately according to the following steps (2) to (7), and performing the following steps: (1) calculating the gold raw material composition through a color calculation table and evenly batching it so that each batch of raw gold has the same color; (2) adding borax to the No. 1 graphite crucible and spreading it on the bottom, then adding the gold raw material, turning on the medium frequency furnace, adjusting the power to 20kw and heating for 2min, then adjusting the power to 50kw and heating for 5min, and then adjusting the power to 100kw until it melts; at the same time, heating the vertical mold to about 150°C; (3) adding potassium nitrate to the molten gold raw material, then adding borax, and stirring until there is no borax residue and other residues on the surface of the gold liquid. Other impurities are removed, and the vertical mold is smoked with an acetylene gun; (4) The gold ingot in step (3) is cast in the vertical mold. When the casting is halfway done, a sample is taken for inspection. During the process, an acetylene gun is used to ignite the fire, which can maintain the temperature of the molten gold and further prevent impurities from entering the vertical mold with the molten gold and adhering to the surface of the gold ingot or entering the inside of the gold ingot. At the same time, the No. 2 graphite crucible starts working from step (2); (5) The gold ingot in the vertical mold is taken out, and after acid quenching and water cooling, the surface of the gold ingot is wiped with a cloth. Then, the surface of the gold ingot and the ingot head are baked with an acetylene gun for 20 seconds, and the fan is cooled for 5 minutes, and the ingot head is cut off; (6) The ingot head is pressed into a thin sheet by a press, and the gold ingot is cut into gold blocks of different specifications by a punch press; (7) The thin sheet and gold block obtained in step (6) are weighted.

[0007] Furthermore, in step (3), the amount of potassium nitrate added is 20 g, which is added in 5 portions.

[0008] Furthermore, in step (3), the amount of borax added is 100 g / time, and is added 4 times in total.

[0009] Furthermore, in step (6), the thickness of the thin sheet pressed by the ingot head is 5 mm.

[0010] Furthermore, in step (6), the gold ingot is cut into gold nuggets of different specifications such as 420-450 g, 50-100 g, 10-20 g, and 2-5 g.

[0011] The present invention calculates various incoming raw materials and divides them into batches so that each batch of gold has the same color. The gold raw materials can be sponge gold, gold nuggets, flake gold, etc. The raw materials have strong adaptability and can process gold raw materials with single impurities exceeding the standard and color lower than the national standard 1# gold standard. A medium frequency furnace is used, and two 60# graphite crucibles are configured for melting, which greatly increases the efficiency of melting the gold raw materials. After melting, potassium nitrate and borax are added for slagging and slagging, which can effectively remove impurities in the gold raw materials without entering the purification system for purification again. After slagging and slagging, the gold liquid is cast in a vertical mold, and after demolding and acid quenching and cooling, it can be cut into gold nuggets of different sizes to achieve fast and accurate weight matching. The 1# gold ingots produced by the weight matching method have better surface quality and stable color, which has a good promoting effect on improving efficiency, shortening production cycle, saving costs, and reducing environmental pressure in the process of continuous casting of national standard 1# gold ingots in large-scale precious metal smelters, and has good promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a calculation table for the purity of the three gold nugget raw materials in Example 1; Figure 2 The test reports of the three gold particle samples in Example 1; Figure 3 This is a color calculation table for the six raw materials in Example 2; Figure 4 The chemical composition test report of gold ingots produced from 7 batches of raw materials in Example 2; Figure 5 This is a color calculation table for the 9 raw materials in Example 3; Figure 6 Chemical composition test report of gold ingots produced from 7 batches of raw materials in Example 3; Figure 7 To compare the surface quality of gold ingots produced by the two methods; Figure 8 It is the Shanghai Gold Exchange GBT 4134-2019 gold ingot standard. DETAILED DESCRIPTION

[0013] Example 1

[0014] The three kinds of gold nugget raw materials of high, medium and low purity are granulated and weighed respectively according to the existing granulation method. During each granulation process, gold particle samples are randomly picked for chemical composition testing. Figure 1 This is a calculation table for the purity of three types of gold nugget raw materials. Figure 2 These are 3 gold particle sample test reports.

[0015] pass Figure 2Comparing the granulation analysis report with the calculation table, the results of gold particle 1 and the color calculation table are basically consistent; gold particle 2 is slightly higher than the color calculation table, but the impurity element Pb exceeds the gold ingot standard and cannot be used; gold particle 3 exceeds the gold ingot standard in terms of both gold color and single impurities. The above results are caused by the high-frequency melting used in granulation, the gold liquid cannot be effectively rolled under the action of the magnetic field, and it cannot be oxidized to form slag and slag, and the content of impurity elements cannot be effectively reduced, which directly affects the quality of gold ingots.

[0016] Example 2

[0017] The gold raw materials consist of 6 kinds of materials, namely flakes, gold nuggets and sponge gold, with a total weight of 630 kg. The impurity elements Ag and Cu and the total gold color of flake material 1 and flake material 2 do not meet the national gold ingot standard. The gold nugget material 1, sponge gold 1 and sponge gold 2 have higher gold colors. The above gold raw materials are evenly divided into 7 batches after calculation through the color table, and are weighted according to the weighting method of the present invention, and samples are taken for chemical composition detection. Figure 3 This is the color calculation table for 6 kinds of raw materials. Figure 4 This is a test report on the chemical composition of gold ingots produced from 7 batches of raw materials. The purity calculation method is to calculate the proportion according to the element content and weight of each gold component so that the content of each element is close to the standard content.

[0018] It can be seen from the chemical composition test report of the gold ingots that the obtained gold ingots have consistent color and relatively consistent chemical composition. The content of Cu and Fe impurity elements is slightly lower than that of the raw materials, and both meet the national 1# gold ingot standard. The above materials can be uniformly weighted to achieve a whole.

[0019] Example 3

[0020] The gold raw materials consist of 9 materials including flake gold, gold nugget and sponge gold, with a total weight of 630 kg. The gold fineness of gold nugget 1 does not meet the national gold ingot standard. The total gold fineness and impurity element Ag of gold nugget 2 do not meet the national gold ingot standard. The total gold fineness, Ag, Pb and Sb of gold nugget 3 do not meet the national gold ingot standard. The total gold fineness, Cu and Sb of flake gold 1 do not meet the national gold ingot standard. The gold fineness of sponge gold 1, sponge gold 2, sponge gold 3, flake gold 2 and flake gold 3 is relatively high. The gold raw materials are evenly divided into 7 batches after calculation through a fineness table, and are weighted according to the weighting method of the present invention, and samples are taken for chemical composition detection. Figure 5 This is the color calculation table for 9 kinds of raw materials. Figure 6 This is a test report on the chemical composition of gold ingots produced from 7 batches of raw materials. The purity calculation method is to calculate the proportion according to the element content and weight of each gold component so that the content of each element is close to the standard content.

[0021] It can be seen from the chemical composition test report of the gold ingots that the obtained gold ingots have consistent color, relatively consistent chemical composition, and the content of impurity elements is slightly lower than that of the raw materials. They all meet the national 1# gold ingot standard. The above materials can be uniformly weighted to achieve a whole.

[0022] Example 4

[0023] The same batch of gold raw materials was divided into two parts, and gold ingots were produced by weighting using the granulation method and the method of the present invention respectively. The surface quality of the gold ingots obtained by the two methods was compared. Figure 7 The surface quality comparison of gold ingots obtained by two methods is shown in Figure 2. Figure 8 It is the Shanghai Gold Exchange GBT 4134-2019 gold ingot standard. It can be seen that the gold ingot surface obtained by the granulation method has white spots formed by impurities and obvious cracks. The gold ingot surface obtained by the counterweight method of the present invention is smooth and clean, without obvious impurities, and meets the national gold ingot standard. In summary, it can be seen that compared with the existing granulation method for counterweighting gold ingot production, this method uses a medium frequency furnace to melt the gold raw material. The gold liquid effectively rolls under the action of the magnetic field, so that the color of the counterweight gold block reaches uniformity, which is good for the full-automatic continuous production of gold ingots. Two 60# graphite crucibles are used alternately, which greatly shortens the production cycle; the ingot head is pressed to a thin sheet by a press to directly counterweight, ensuring that there is no residual gold residue and avoiding secondary melting and casting. The gold raw material has strong adaptability, and the melting process can oxidize the gold liquid to slag and remove slag, which can further reduce the impurity content of the gold block, and the surface quality of the gold ingot produced is better. It can process gold raw materials with excessive single impurities and gold purity lower than the national standard 1# gold, without the need to enter the purification system for purification again. At the same time, the high-purity gold raw materials are effectively utilized, which has a good promoting effect on large-scale precious metal smelting plants to integrate parts into a whole, save costs, and reduce environmental pressure. It has a good promotion value in the industry.

Claims

1. A method for balancing weight of national standard 1# gold ingot, characterized in that: A medium frequency furnace is equipped with two graphite crucibles and used alternately according to the following steps (2) to (7). The steps of the weight balancing method are as follows: (1) Calculate the gold raw material composition using the color calculation table and evenly divide it into batches; (2) Add borax to the No. 1 graphite crucible and spread it on the bottom. Then add the gold raw material, turn on the medium frequency furnace, adjust the power to 20kw and heat for 2min, adjust the power to 50kw and heat for 5min, and adjust the power to 100kw until it melts; at the same time, heat the vertical mold to about 150℃; (3) Add potassium nitrate to the molten gold raw material, then add borax, and stir until there is no borax residue or other impurities on the surface of the gold liquid. At the same time, use an acetylene gun to fumigate the vertical mold; (4) Casting the product of step (3) into the vertical mold, using an acetylene torch to ignite the fire, while graphite crucible No. 2 starts working from step (2); (5) Take out the gold ingot in the vertical mold, quench with acid and cool with water, wipe the surface of the gold ingot with a cloth, then use an acetylene gun to bake the surface of the gold ingot and the ingot head for 20 seconds, cool with a fan for 5 minutes, and cut off the ingot head; (6) The ingot head is pressed into thin sheets by a press, and the gold ingot is cut into gold blocks of different specifications by a punch press; (7) The thin sheet and gold nugget obtained in step (6) are weighted.

2. A weight balancing method for a national standard 1# gold ingot according to claim 1, characterized in that: In step (3), the amount of potassium nitrate added is 20 g, which is added in 5 portions.

3. A weight balancing method for a national standard 1# gold ingot as described in claim 1, characterized in that: In step (3), the amount of borax added is 100 g / time, and it is added 4 times in total.

4. The method for balancing weight of a national standard 1# gold ingot according to claim 1, characterized in that: In step (6), the thickness of the sheet pressed by the ingot head is 5 mm.

5. The method for balancing weight of a national standard 1# gold ingot according to claim 1, characterized in that: Step (6), cutting the gold ingot into gold nuggets of different specifications such as 420-450g, 50-100g, 10-20g, and 2-5g.

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